Abstract: In order to reduce the variety of connector bodies needed for connecting electrical apparatus such as an automobile radio to factory-installed cabling of a motor vehicle having a mating connector for connection to the electrical apparatus, a composite connector is provided having a front unit with two sets of contacts respectively interconnected by a circuit board, of which the first set is designed to interfit with the mating connector of the vehicle and the second set is designed to interfit with the contacts of a second unit of the composite connector. That second unit has a set of contacts connected to a circuit board which carries circuit components for protection of electrical circuits from external interference. A flat parallel conductor cable is introduced through a slot in the second unit for connection to its circuit board before the circuit board is put in place.